...N

The C₂N data are now available at the Cologne Database for Molecular Spectroscopy (www.cdms.de, see Müller et al. 2001).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... envelope

See for example the SiC₂ mapping of IRC+10216 by Gensheimer et al. (1995).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

...N

These are the lines at 129 980.48 MHz, 200 914.8 MHz, and 248 190.2 MHz.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... of

The formula was derived using Eq. (1) from Turner (1991).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... function

The partition function for a temperature T has been calculated by $Q(T)=\alpha \cdot T^{\beta}$, where $\alpha$ and $\beta$ are determined by the Q(T_i) values given by the Pickett program. For the C₂N radical $\alpha =$ 7.1 and $\beta =$ 1.2 .

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

...12

Taking the temperature uncertainty $\pm$4 K into account we get $N_{\rm T}=3.5{-}5.6 \times 10^{12}$ cm^-2.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.